KR100760947B1 - Routing protocol for the wireless sensor network - Google Patents

Abstract

A method for providing a routing protocol in a wireless sensor network is provided to reduce the necessary memory capacity of sensor nodes because there is no need of a routing table, determine a transmission path independently, and reduce load within the whole system. A sink node(10) instructs the setting of a level value to each sensor node(20), and the each sensor node sets up its own level value. The each sensor node collecting sensor events transmits a sensor event to the sink node via a sensor node with an upper level value from a sensor node with a lower level value. The sink node receives the sensor event transmitted from the each sensor node.

Description

Routing Protocol for Wireless Sensor Network System

1A is a schematic diagram of a wireless sensor network system in accordance with the present invention

1b is an algorithm of a routing protocol according to the present invention.

2 is an algorithm of a level setting step according to the present invention.

3A to 3B are state diagrams of the level setting step according to the present invention.

4 is an algorithm between sensor nodes according to the present invention.

5A to 5C are diagrams illustrating a state of exchanging data packets between sensor nodes according to the present invention.

6 is a simulation result of the routing protocol according to the present invention NS2

※ Explanation of code used in drawing ※

10: sink node 20: sensor node

The present invention relates to a routing protocol providing method of a wireless sensor network system. More particularly, the present invention relates to a wireless sensor network including a plurality of sensor nodes for collecting and transmitting sensor events and a sink node for receiving collected sensor events from the sensor nodes. The present invention relates to a routing protocol providing method used in a system.

In general, the development of communication technology has led to the creation of an environment in which a user can freely access a network regardless of a computer or a network. This is known as ubiquitous and the recent researches in the field of communication technology are developing with the goal of incorporating such ubiquitous into real life.

The core technology of such ubiquitous is wireless sensor network system. A typical sensor network system is a sensor node that senses, measures, and floods physical data such as light, sound, temperature, and movement in the physical space, and a central primary node (sink node, which receives and analyzes data flooded from the sensor node). sink-node).

Typically sensor nodes have their own computing power and are sensors that can communicate with other nodes. In addition, sensors for detecting various events (temperature, barometric pressure, humidity, etc.) occurring at the place of deployment, a local storage module for identifying the current place, and sending information data on the detected event, or base station or other sensing A battery for supplying energy for driving a communication module for receiving information data transmitted from a device, a processor for arithmetic processing of the sensor, a local storage module, a communication module, and the like. It includes. The self-calculation capabilities enable the self-analysis of the information obtained from the sensors.

In addition to the raw results obtained from the sensor, the results of the analysis can be centralized to several nodes in the network through the communication of each node.

Therefore, the sensor network needs a sensor and communication equipment that can collect data and communicate with other nodes, and a routing protocol that can help communication between sensor nodes and an application that can analyze information obtained by the sensor.

In addition, since sensor networks have many similarities with Ad-Hoc, which has mobility management and peer-to-peer communication, techniques for routing protocols for mobility management and data transmission paths of sensor networks have been developed. It follows from Hoc.

When the Ad-Hoc routing protocol is largely divided into two categories, the routing protocol of Proactive method having routing information of all nodes by updating routing information according to periodic packet transmission and reception between each node and destination according to data transmission request There is Reactive routing protocol to get routing information up to. Both approaches have their advantages and disadvantages.

In the proactive routing protocol, since the source node always has the routing information of the destination node, it is possible to perform fast data transfer according to the routing information that the data transfer node has. However, since the routing information of a large number of nodes must be maintained at all times, a large amount of memory is required for each node, and the load of packet transmission between nodes to maintain the latest information always depends on the entire network system.

Reactive routing protocol requires routing information only for data transmission, so it takes some delay at the beginning of sending data, but it does not burden each node. When considering the limitations of the sensor network with these two routing methods, a reactive routing protocol with less load on the sensor nodes is more suitable.

The proactive routing protocols described above include DSDV, CGSR, WRP, and the like, and the reactive protocols of ADSV, DSR, ABR, and the like.

However, both the proactive and the reactive routing protocols require a large amount of memory for each node in terms of operating with a routing table, resulting in a large load on the entire system.

In addition, communication is the most energy consuming in tasks such as sensing each sensor node to collect surrounding information, processing to analyze sensed information, and communicating raw and processed information to the sink node. However, although the two routing protocols provide a basic routing table, there is a problem in that energy consumption for providing a new routing table is increased when the routing is changed according to the routing table.

In addition, in addition to the inconvenience of having to go through various tasks at each node in order to change the routing table, there was a problem that a separate load is applied to the entire system accordingly.

Accordingly, the present invention has been made to solve the above problems, and an object thereof is to provide a routing protocol that does not require a routing table.

In addition, by providing a routing protocol that does not require a routing table, the purpose is to lower the required memory capacity of each sensor node, and that each sensor node can act independently to deliver sensor events.

It is also an object of the present invention to extend the life of each sensor node by reducing the energy consumption of each sensor node by providing a routing protocol that does not require a routing table.

It also aims to reduce the load in the system by providing a routing protocol that does not require a routing table, thereby eliminating many of the tasks associated with changing the routing table.

In order to solve the above problems, the present invention is a routing protocol of the sensor network consisting of a plurality of sensor nodes for collecting and transmitting sensor events in the area to be sensed and a sink node for receiving the sensor events, each sink node A level value setting step in which a sensor node sets a level value by instructing a sensor node to set its own level value, and each sensor node that collects sensor events passes from a lower level sensor node to a higher level sensor node. Event sending step of transmitting a sensor event to the sink node, and the sink node is a routing protocol providing method of a wireless sensor network system comprising an event receiving step of receiving a sensor event transmitted by each sensor node.

The level value setting step may include (a) the sink node setting its level value to 0 and storing the level value as 1 in a level setting packet which is a level setting message, and (b) the sink node Broadcasting the level setting packet to a peripheral sensor node; (c) receiving the level setting packet by the peripheral sensor node; (d) a level value received by the sensor node receiving the level setting packet and its own value; Comparing the level value and setting the small value as its own level value; (e) the sensor node that has set the level value increases the unit value to its level value, updates the level setting packet, and then updates the level value. And broadcasting the level setting packet to a peripheral sensor node.

(f) Steps (c) to (e) may be repeated to set the level of each sensor node, including setting a level value for all sensor nodes in the sensor network.

In addition, in step (b), the sink node broadcasts the level request packet to the neighboring sensor nodes, and waits until all the sensor nodes in the network set the level value, but the waiting time is the range of the sensing area or the sensor node. Set to correspond to a number.

In this case, the unit value in the step (e) is preferably set to 1.

In addition, the level value setting step may be performed once at the time of network setup, and may be periodically reset by an operator later.

In addition, the event transmission step (g) each sensor node collecting a sensor event broadcasts a level request packet, which is a level request message including its level value to the surrounding sensor node, (h) the peripheral sensor node Receiving the level request packet, (i) comparing, by the sensor node receiving the level request packet, its level value with the received level value, and (j) comparing the received level value with the received level value. If it is smaller than the level value, the level response packet is sent to the sensor node that sent the level response message. If the level value is greater than the level value and the received level value, the level response packet is sent to the sensor node that sent the level request packet. (K) the sensor node receiving the level response packet includes selecting a sensor node that responded first and delivering sensor events collected by the sensor node from the lower level to the higher level. It is desirable to send an event.

In this case, it is preferable that the level request packet includes an ID of each sensor node because the sensor node that transmits the level request packet can identify the sensor node that transmits the level response packet.

Also, if the level value of the sensor node is smaller than the received level value in step (j), if the current state of the sensor node to which the level response packet is sent is another operation or a state in which communication is impossible, the sensor that has transmitted the level request packet. The step of not sending a level response packet to the node is desirable because it can determine whether or not to transmit according to the state of each sensor node.

In this case, it is preferable that the level response packet includes an ID of each sensor node because the sensor node that transmits the level request packet can identify the sensor node that transmits the level response packet.
Hereinafter, an embodiment of a routing protocol providing method of a wireless sensor network system according to the present invention will be described in detail with reference to the accompanying drawings.

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1A shows a schematic diagram of a wireless sensor network system provided with a routing protocol according to the present invention. As shown in the drawing, in the wireless sensor network system, a plurality of sensor nodes 20 having sensors for collecting surrounding environment information (sensor events) are disposed in a region A of a predetermined range, and the sensor nodes 20 are disposed. It includes a sink node 10 for receiving the sensor event collected by. At this time, each sensor node 20 is disposed in the network, the initial level value is set to infinite, and is configured to transmit and receive sensor events collected from each other through a routing protocol according to the present invention.

1B illustrates an algorithm for receiving a sensor event through a routing protocol of a sensor network system according to the present invention. As shown in the drawing, in the method in which the sink node 10 receives a sensor event transmitted from each sensor node 20, the sink node 10 sets a level value to each sensor node 20. Instructing each sensor node 20 sets its own level value (S10). Each sensor node 20 having a set level value transfers the collected sensor event from the sensor node 20 having the lower level value to the sink node 10 via the sensor node 20 having the upper level value. (S20). The sink node 10 receives the sensor event transmitted by each sensor node 20 (S30).

In this manner, the sink node 10 receives the sensor events collected by each sensor node 20.

2 is an algorithm showing in detail the level setting step of the routing protocol according to the present invention. 3A shows that the sink node transmits a level setting packet, and FIG. 3B shows a state in which a level is set for each sensor node.

As shown in FIG. 2, the sink node 10 initially sets its level value to 0 (S11), and stores the level value as 1 in a level setting packet to be transmitted (S12). In this case, the level setting packet includes a message for comparing the received level value with its own level value and setting a smaller value as its own level value. It is assumed that the smaller the level value is the higher level value. Referring to FIG. 3A, the sink node 10 broadcasts the level setting packet in which a level value is stored to 1 to all nodes within a hop range (S13), and all sensor nodes within the transmission range are transmitted. The broadcasted level setting packet is received (S14). Each node receiving the level setting packet compares the level value stored in the received level setting packet with its own level value (S15).

At this time, if the level value of the user is smaller than the received level value, the level value of the user is maintained as it is (S16a). If the level value of the user is greater than or equal to the received level value, the received level value is set to the level value of the user. (S16b). The sensor node 20 that first receives the level setting packet broadcasted from the sink node 10 or another sensor node has its own level even though any level value is received because the initial value is set to infinity. It will be set to a value. The sensor node 20, which has set the received level value as its own level value, updates the level setting packet by increasing a predetermined unit value to the level value of the level setting packet (S17), and sets the unit value to 1. It is preferable. After the sensor node 20 updates the level setting packet, the sensor node 20 broadcasts the level setting packet updated with the unit value around itself (S18). Referring to FIG. 3B, two level values may be set in the sensor node 20 by the above-described method, and after the sensor node 20 receiving the level setting packet sets the level value, the level value is updated. By repeating the process of broadcasting the level setting packet again, all the sensor nodes 20 in the sensor network can set the level value.

In addition, the sink node 10 does not switch to the normal operation mode, that is, the sensor event receiving mode immediately after transmitting the first level setting packet, and waits a predetermined time until all sensor nodes in the network set the level value. do. At this time, the waiting time may be manually set by an operator according to the range of the sensing area and the number of sensor nodes.

All the sensor nodes set the level value by the above-described method, and the setting of the level value needs to be performed once at the time of network setup. However, after a time has elapsed, when an external shock or other communication is not possible or when there are many sensor nodes which have reached the end of their life due to battery consumption or the like, the operator may periodically instruct the level reset.

Next, a method of transmitting the sensor event collected from each sensor node to the sink node will be described.

4 is an algorithm between sensor nodes of a routing protocol according to the present invention. 5a to 5c show the exchange of data packets between sensor nodes.

5A to 5C, the first sensor node 21 collecting the sensor event may include a second sensor node 22, a third sensor node 23, a fourth sensor node 24, which are peripheral sensor nodes. The fifth sensor node 25 broadcasts a level request packet which is a level request message including its own level value (hereinafter referred to as LREQ packet) (S21). In this case, the second sensor node 22, the third sensor node 23, and the fourth sensor node 24 have higher level values than the first sensor node 21, and the fifth sensor node 25 is formed of a first sensor node 25. Assume that it has a lower level value than one sensor node 21. In addition, the LREQ packet includes an ID (hereinafter referred to as "ID") of the corresponding sensor node.

The second sensor node 22, the third sensor node 23, the fourth sensor node 24, and the fifth sensor node 25 receive the LREQ packet broadcast from the first sensor node 21 (S22). In step S23, it is determined that the level value included in the received LREQ packet is compared with its level value. At this time, when the received level value is greater than or equal to its own level value, that is, the fifth sensor node 25 having the lower level value does not respond (S24a).

In addition, the second sensor node 22, the third sensor node 23, and the fourth sensor node 24 having the upper level value respond, but their current state is BUSY (work in progress) or communication. It is determined whether this state is impossible (S24b). The state in which communication is impossible is a state in which communication is impossible due to lack of battery or external shock. If the fourth sensor node 24 is sensing the external environment information or transmitting a sensor event to another sensor node or other task or communication is not possible and the second sensor node 22 and the third sensor node are not in communication. If (23) is not the case, the fourth sensor node 24 does not respond (S25a), and the second sensor node 22 and the third sensor node 23 transmit the LREQ packet to the first sensor node. In step S25b, an LREP packet, which is a level response packet including its own level value and its ID, is transmitted (S25b).

The first sensor node 21 receives LREP packets from the two sensor nodes. If the response of the second sensor node is faster than the response of the third sensor node, the first sensor node 21 selects the second sensor node that has the fastest response, The collected sensor event is delivered (S26).

In the above-described method, a sensor event is transmitted from a sensor node having a lower level value to a sensor node having a higher level value, and ultimately, the sink node receives sensor events collected from each sensor node. Therefore, even if a separate routing table is not mounted on each sensor node, the sensor node can independently transmit sensor events to the sink node, and thus there is no need for memory capacity to preserve the routing table.

Fig. 6 shows the results of simulating the routing protocol according to the present invention described above in NS2. NS2 is a widely used network simulation tool that provides various environments suitable for simulating various Internet protocols such as TCP, routing protocols, multicast protocols, Real Time Protocol (RTP) and Scalable Reliable Multicast (SRM). .

As shown in FIG. 6, it can be seen that in the conventional AODV, the network control packet is rapidly increasing as the number of nodes increases. In contrast, the present invention shows that the network control packet hardly increases compared to the increase in the number of nodes. In addition, although the RREQ (Route Request) used in AODV is 24 bytes, LREQ and LREP used in the present invention are composed of 8 bytes, so the size of a control packet required for routing is also small. Therefore, it can be seen that the load on the sensor network can be reduced by using the routing protocol according to the present invention.

In addition, the low network control packet means that the number of communication between each node is small, thereby reducing the battery consumption of each node can extend the life of the sensor node.

The scope of the present invention is not limited to the above embodiments, but may be embodied in various forms of embodiments within the scope of the appended claims. It will be understood that those skilled in the art to which the invention pertains may fall within the scope of the claims without departing from the gist of the invention as claimed in the claims.

As described above, the method for providing a routing protocol of the wireless sensor network system according to the present invention has an advantage of lowering the required memory capacity of the sensor node of the sensor network because a routing table is not required, and thus, within the entire system. There is an effect that can reduce the load.

In addition, by providing a routing protocol that does not require a routing table, the energy consumption of each sensor node is reduced, thereby extending the life of each sensor node.

In addition, by providing a routing protocol that does not require a routing table, it is possible to eliminate various tasks involved when the routing table is changed, thereby reducing the load in the network.

Claims (10)

In a routing protocol providing method of a wireless sensor network system comprising a plurality of sensor nodes for collecting and transmitting sensor events in a region to be sensed and a sink node for receiving the sensor events, A level value setting step of the sink node instructing each sensor node to set a level value so that each sensor node sets its own level value; An event transmission step of transmitting a sensor event to each of the sink nodes via a sensor node having a higher level value from a sensor node having a lower level value; And The sink node comprises an event receiving step of receiving a sensor event transmitted by each sensor node; routing protocol providing method of a wireless sensor network system, comprising: The method of claim 1, The sensor node provides a routing protocol for a wireless sensor network system, characterized in that the initial level value is infinite before the level value setting step. The method of claim 2, The level value setting step, (a) the sink node setting its level value to 0 and storing the level value as 1 in a level setting packet which is a level setting message; (b) the sink node broadcasting the level setting packet to a peripheral sensor node; (c) the peripheral sensor node receiving the level setting packet; (d) comparing the level value received by the sensor node receiving the level setting packet with its own level value and setting a small value as its own level value; and (e) updating the level setting packet by increasing the unit value to its level value by the sensor node that has set the level value, and then broadcasting the updated level setting packet to the neighboring sensor node. (f) repeating steps (c) to (e) to set level values of all sensor nodes in the sensor network; providing a routing protocol of a wireless sensor network system, comprising: The method of claim 3, wherein In the step (b), the sink node broadcasts the level setting packet to the neighboring sensor nodes, and waits for all the sensor nodes in the network to set the level value, but the waiting time depends on the sensing area range or the number of sensor nodes. Routing protocol providing method of a wireless sensor network system, characterized in that the corresponding setting The method of claim 4, wherein In step (e), the unit value is a routing protocol providing method of a wireless sensor network system, characterized in that 1. The method according to any one of claims 1 to 5, The level value setting step may be performed once at the time of network setup, and may be periodically reset by an operator later. The method of claim 1, The event transmission step (g) each sensor node collecting the sensor event broadcasting a level request packet, which is a level request message including its level value, to the neighboring sensor nodes; (h) a peripheral sensor node receiving the level request packet; (i) comparing, by the sensor node receiving the level request packet, its level value with the received level value; (j) When the level value is smaller than the received level value by comparison judgment, the level response packet, which is a level response message, is transmitted to the sent sensor node. When the level value is larger than the received level value, the level response Not sending a packet to the sensor node that sent the level request packet; (k) The sensor node receiving the level response packet selects the sensor node that responded first and forwards the sensor events collected by the sensor node. The method of claim 7, wherein The level request packet includes a routing protocol for a wireless sensor network system, characterized in that it comprises an identification of each sensor node. The method of claim 8, If the level value is smaller than the level value received in the step (j), if the current state of the sensor node to which the level response packet is sent is in a different operation or in a state in which communication is impossible, to the sensor node transmitting the level request packet. Routing protocol providing method of a wireless sensor network system comprising the step of not transmitting a level response packet The method of claim 9, The level response packet includes a routing protocol providing method of a wireless sensor network system, characterized in that it includes identification of each sensor node.

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